ECONOMIC EVALUATION OF AESTHETIC AMENITIES: A CASE STUDY OF RIVER VIEW1

ABSTRACT: Presence of a river in an urban setting may contribute positively to an aesthetically pleasing environment. Such aesthetic effects are not typically linked to specific economic activities and occur, for example, when residents are exposed to a river-view. Qualities enhancing the aesthetic value of the river include the presence of parks, trails, and vegetation along the riverbanks. The value of aesthetic amenities provided by the South Saskatchewan to the City of Saskatoon residents was estimated in this study using non-market methods. The implicit price of the river view was estimated using the Hedonic Price Model, whereas value through willingness to pay for property taxes or higher rents were also estimated using actual market data. The total annual value of the river to the City of Saskatoon through addition of aesthetic amenities was estimated at $1.2 million in 1989 dollars.     

Formation of polyester blends by a recombinant strain ofPseudomonas oleovorans: Different poly(3-hydroxyalkanoates) are stored in separate granules

WhenPseudomonas oleovorans (GPo1) is grown on sodium octanoate under ammonium limiting conditions, it is able to accumulate a copolyester consisting of medium chain length 3-hydroxyalkanoic acids (PHA_m). 3-Hydroxybutyrate is only incorporated in trace amounts. WhenP. oleovorans is equipped with the PHB biosynthetic genes ofAlcaligenes eutrophus (GPo1[pVK101::PP1]), it forms a polyester containing major amounts of 3-hydroxybutyrate. The resulting polymer however is a blend of PHA_m and PHB, rather than a copolymer of 3-hydroxybutyrate and medium chain length 3-hydroxyalkanoic acids [11]. To establish whether PHA_m and PHB molecules are stored in the same or separate granules by this recombinantP. oleovorans strain, we studied polymer forming cells by freeze-fracture electron microscopy. This approach is possible because previous freeze-fracture electron microscopy studies on PHA_m and PHB accumulating strains have shown that PHA_m and PHB granules can be distinguished from each other: PHA_m granules from mushroom-like structures, whereas PHB granules from needle structures during freeze-fracturing. In this paper we show that stationary phase cells of GPo1[pVK101::PP1] contained both mushroom and needle-like structures, indicating that PHA_m and PHB chains were stored in separate granules. To be able to determine whether the separation of PHA_m and PHB is complete, the respective granules were separated on sucrose gradients. A total cell extract of GPo1[pVK101::PP1] which was subjected to sucrose gradient centrifugation revealed two white bands of different densities: the upper band with a density of 1.05 g/mL consisted exclusively of PHA_m granules, while the lower band with a density of 1.19 g/mL consisted of PHB granules only. Thus, when bacteria synthesize both PHA_m and PHB, the resulting polymer chains are segregated completely and stored in separate granules.     

TECHNICAL AND INSTITUTIONAL ASPECTS OF SEWAGE EFFLUENT-IRRIGATION WATER EXCHANGE,TUCSON REGION1

ABSTRACT .Many growing municipalities near irrigated agriculture are advocating a transfer of water now utilized for irrigation to municipal use. Alternatives are presented whereby this water can be transferred to municipal use in exchange for treated sewage effluent. The irrigation water would in effect be cycled through the municipal system prior to use on the farms. A case study of the Tucson region illustrates the relevant legal, economic and technical aspects. Effluent could be delivered to irrigators in Avra Valley at a cost less than that now paid for water pumped from declining water tables. In return the City of Tucson could import ground water now being used for irrigation through an existing pipeline which presently cannot be used because of a court injunction obtained by the irrigators. It appears that such an exchange agreement could be made without modification of existing statutory law. Similar exchange arrangements may prove to be feasible in other regions containing irrigated agriculture. Increased efficiency of water use can be achieved avoiding external effects which commonly arise in a direct transfer and are difficult to evaluate. High quality water is allocated to municipal use whereas nutrient-rich sewage effluent is transferred to irrigation.     

NEW APPROACHES TO COMPREHENSIVE PLANNING IN CANADA1

ABSTRACT. In 1970, the Canadian Federal Government passed the Canada Water Act which provides for a co-operative federal-provincial approach to water resource management. The purpose of this paper is to outline our definition of comprehensive planning and the approach being taken under the new legislation. Two basic premises underly the definition. They are that resource management consists of an array of problems and that the prime function of planning is to provide information for decision making. The definition of comprehensive planning is embodied in a general statement and a set of principles. The principles define the approach that should be taken to provide adequate information for decision making in today's complex environment. A brief resume of the jurisdictions for water management in Canada leads to a discussion of a joint federal-provincial comprehensive study of the Qu'Appelle River Basin in Southern Saskatchewan. The basin and the study are described briefly. This is followed by an outline of the economic and social considerations which are being incorporated into the comprehensive planning study for the basin.     

THE DEVELOPMENT OF A MODEL TO EVALUATE HYDROLOGIC RISK IN WATER RESOURCE SYSTEM DESIGN1

In this paper, a procedure for analyzing a water resource system with special emphasis on evaluation of acceptable economic risk due to occasional failures to deliver water is proposed. The basic methodology includes the development of a simple mathematical model which describes the physical hydrologic and economic characteristics of a single reservoir irrigation and city water supply system and an evaluation of economic benefits of the system with full and partial deliveries of water. The system is simulated for various combinations of decision variables (system magnitudes) and an optimum design is obtained by response surface technology. Emphasis is placed on the basic model and methodology although, in order to introduce some realism, the procedure is applied to data based on the existing reservoir system on the South Concho River in West Central Texas.     

FINANCING PRIVATE WATER RESOURCE DEVELOPMENT: ANALYSIS OF A STATE LOAN PROGRAM1

ABSTRACT. A State loan program was analyzed for its effects on groundwater development in Wyoming. The analysis focused on the effects of low-interest State financing on the economic feasibility of investments in center-pivot sprinkler irrigation systems. The feasibility analysis indicated that investments in sprinkler systems for production of cash crops are highly profitable, and would frequently be carried out whether or not the State loan program were available. Investments in sprinklers for production of forage crops are perhaps frequently made attractive by the loan program. Thus, while the program appears to have accelerated the pace of private water resource development in Wyoming, it has also subsidized some investments that would have been carried out regardless of the program's existence. Further analysis indicated that sprinkler investments carried out with State financing contribute substantially to firm growth when cast crops are grown, but have less marked, and sometimes negative, effects on growth when forage crops are produced. Some positive effects of the loan program on southeast Wyoming's regional economy were noted, though a complete empirical analysis of regional impacts was beyond the scope of the study.     

找准经济与环境协调发展的切入点

实施可持续发展战略,就是要实现经济建设与环境保护协调发展。本文从佳木斯市实际出发,提出了环境保护职能部门如何参与经济结构调整以实现经济与环境协调发展的意见和建议。     

泥石流与人类经济活动

山地是泥石流与人类共存的环境,泥石流作用于山地环境,强烈地影响人类经济活动：人类经济活动也作用于山地环境,强烈地影响泥石流。泥石流对山地环境的危害,主要为破坏地表、破坏生态系统和淤堵江河;泥石流对人类及其经济活动的危害,主要为破坏城镇,村庄,工矿,交通水利水电工程,农田和人类自身的安全。泥石流危害的结果,能导致山地坡面破碎化、沟口沙石化、河床宽浅化和植被逆向演替化,以及耕地贫瘠化、经济发展滞后化和     

揭开武汉东湖蓝藻水华消失之谜

水华（亦称湖靛）是湖泊富营养化最恶劣的表征之一。武汉东湖７０年代至１９８４年间每年夏季出现蓝藻水华,１９８５年起突然消失,至今已有１４年没有重现,原因何在？通过三次设在湖里的围隔试验,证明鲢鳙的大量放养,是水华消失的决定性因素。     

中国经济实现持续增长面临的城市化滞后的挑战

我国人口城镇化滞后的根本原因在于计划经济体制下形成的二元经济结构和城乡隔离的户籍管理制度没有在工业化进程和市场经济体制建立进程中予以破除。而城镇化的滞后将给我国经济实现持续增长带来诸多挑战，包括有效需求不足、农业生产率低下、产业结构难以升级等。文章特别阐明通过包括户籍制度、就业制度和土地承包制度在内的制度创新，加快人口城镇化的步伐，促进经济持续稳定的增长。